Monday 11 August 2008 19.01 EDT
First published on Monday 11 August 2008 19.01 EDT

Arthur Scargill is a brave man. He was brave to come to the climate camp at Kingsnorth last week. Though we disagreed with most of what he said, he earned our respect for his willingness to debate. He is brave to return to public life after suffering one of the nastiest vilification campaigns in British history, and is brave to be fighting for coal again. He is especially brave to offer to asphyxiate himself in the interests of science. Many people would be willing to help him perform this experiment at the earliest opportunity.

But he is also wrong. In his article last week demanding a return to coal and accusing me of selling out, Scargill suggested that radioactive discharges are more dangerous than carbon emissions. This, of course, is nonsense; but if he really believes it he should be campaigning against the burning of coal.

The odd and widely ignored truth is that routine radioactive discharges from coal-burning are greater than those produced by nuclear plants. Coal contains trace amounts of uranium and thorium. Though these are present at much lower levels than in nuclear fuel, a lot more coal is burned, which means that total emissions are greater. An article in Scientific American last year maintained that levels of ionising radiation in the bones of people living around coal plants are up to six times higher than the levels in people living around atomic power stations.

The people most at risk from the radioactivity associated with coal (not to mention far greater hazards such as dust, heavy metals and sulphur and nitrous oxide pollution) are the workers - both in the mines and in the power plants. Coal mining is associated with some of the most unpleasant industrial diseases ever recorded. Why would a trade unionist wish to expose working people to these dangers, when they could instead be employed, at minimal risk to their health, building and installing wind turbines, wave machines and solar power plants?

Scargill maintains that nuclear power is four times as expensive as coal-fired electricity. There's a standard model for estimating future costs, of which he should be aware, produced by the International Energy Agency. This shows that it's likely to be 10%-50% more expensive to save a tonne of carbon through coal burning with carbon capture and storage than by means of nuclear energy. (Wind power, incidentally, is much cheaper than either.) The agency's figures are not definitive - nothing in this field is - but the estimates it gives are for coal bought at anticipated market prices, not for the much more expensive fuel Arthur proposes: coal produced only from deep mines in the UK.

I feel I need to point out that I have not become an advocate for nuclear power. My position is that environmentalists should stop trying to pick technologies for electricity generation. Instead we should demand a maximum level for the carbon dioxide produced per megawatt-hour, impose a number of other public safety measures, then allow the energy companies to find the cheapest means of delivering it. Otherwise we are in danger of backing the solutions we find aesthetically appealing and delaying the massive carbon cuts that need to be made. If nuclear power meets the very tough conditions I proposed last week, we should no longer oppose it - though that remains a big if. This is too subtle a point for Arthur and other commentators, who are shrieking that Monbiot has gone nuclear.

Scargill claims that the closure of most of the UK's coal plants has not been accompanied by lower carbon emissions. In fact, carbon pollution has faithfully tracked coal burning for the past 18 years. In 1990, when consistent carbon data for the UK began, this country used 108 million tonnes of coal and produced 592m tonnes of carbon dioxide. In 1999, coal consumption fell to its lowest level since 1970 (56m) and the UK's emissions fell to their lowest level since 1990 (540m). Emissions rose in 2006 because coal burning increased when gas prices shot up. They fell back again in 2007 when the gas price dropped. In all cases, coal has been the key swing factor for CO2 production.

When Scargill suggests that, by mining and refining coal, "we can provide all the electricity, oil, gas and petrochemicals that people need, without causing harm to the environment", he shows that he is living in a world of make-believe. He rightly demands that we "end the import of shale oil, tar sands and other so-called unconventional oils" and calls them "the dirtiest fuels on the planet". But while the total carbon emissions from petrol made out of tar sands are 30%-70% higher than those from conventional petroleum, turning coal into transport fuel raises emissions by 85%. The process also requires 10 gallons of fresh water for every gallon of fuel produced. Coal, not tar sand, is the dirtiest fuel on the planet.

When he speaks of a resurgent coal industry, he pictures deep seams hacked out by grimy workers romantically dying of silicosis. But, with a few minor exceptions, this is no longer how coal is produced in the UK. New research I've commissioned, published for the first time here, shows that the industry is planning a great opencast revival. Since January last year, 22 new opencast coal mines or mine extensions have been approved by British planning authorities. Only two schemes - both of them quite small - have been rejected without appeal. My researcher, Ketty Dean, has discovered that mining companies have applied for planning permission for a further 22 schemes, while 11 more applications in England alone are about to be submitted.

Altogether, if the new proposals are accepted, 55 million tonnes of coal extraction is in the pipeline. If we accept the outer limit proposed by the Intergovernmental Panel on Climate Change for the carbon cut required to prevent more than 2C of warming (85% worldwide, which means 95.9% in the UK), the coal these pits will produce equates to the sustainable annual emissions of 280 million people.

This digging can happen only at the expense of the communities Scargill claims to support. The Coal Forum is a government-funded lobby group in which coal companies and civil servants plot against the public interest. Its latest minutes reveal that if - as the Welsh assembly now proposes - there is a minimum distance of 500 metres between opencast pits and the nearest homes, this would "sterilise" all the useful coal reserves in Wales. This means that they could no longer be dug. The pits are viable only if they are allowed to wreck the lives of local people. Even before a lump of clean coal is burned, its extraction trashes the environment.

Arthur Scargill ends his column with a final appeal to reason - by challenging me to a duel. "I am prepared to go into a room full of CO2 for two minutes, if he is prepared to go into a room full of radiation for two minutes." I accept his challenge, as long as I can choose my source of radiation. I invite Arthur to propose a date and send me the name of his second. I hope he can hold his breath.